An HVAC of the vehicle air conditioner is provided with a rotational number controlling device for controlling the rotational number of the blower to adjust a volume of blown air. When controlling the rotational number of the blower by using the rotational number controlling device, since the rotational number controlling device generates heat, a heat radiating unit of the rotational number controlling device (hereinafter, that including the heat radiating unit is simply represented as the rotational number controlling device in the present invention) is installed in an airflow passage of a case of the air conditioner to be cooled by the blown air. A structure of a general HVAC is such that the blower and a unit provided with a heat exchanger are separated from each other and the rotational number controlling device is installed in a duct provided therebetween (refer to FIG. 1 of the Patent Document 1, for example).
There is the HVAC having a structure referred to as a center concentrated-type so as to meet with requirement of downsizing in addition to a separate-type HVAC disclosed in the Patent Document 1. In the center concentrated-type HVAC, components such as an intake box, a blower, a cooling heat exchanger, a heating heat exchanger, a temperature adjusting door and an air delivery door to compose the same are assembled in the vicinity of a vehicle center, thereby making an occupied volume in a vehicle front-rear and right-left direction small (refer to, for example, FIG. 1 of the Patent Document 2; however, an installation position is not specifically disclosed).
In the center concentrated-type HVAC, a duct for connecting the blower and the unit provided with the heat exchanger does not exist or small even if this exists, and the unit itself is required to make an occupied area thereof smaller, so that density of various parts arranged inside is high and it is difficult to secure an installation position of the rotational number controlling device. Therefore, there is an example of installing the rotational number controlling device in the intake box in a center concentrated-type air conditioner (refer to, for example, FIGS. 7 and 8 of the Patent Document 2).